The report, which was unveiled at the organization's annual conference in Las Vegas, lists the total number of on-duty deaths for 2011 as 61.

The total marks the third year of sharp declines from the 105 on-duty deaths in 2008.

"It is certainly good news that the number of firefighter deaths has continued to decrease, reaching an all-time low since our first report in 1977," Rita Fahy, NFPA's manager of fire databases & systems, said in a statement.

"We are grateful for the sacrifices of these brave individuals and are hopeful that with expanded use of codes and standards and other safety initiatives the downward trend in the number of firefighters dying on duty will continue."

Of the 61 firefighters who died, 35 were volunteers, 21 were career, three were employees of state land management agencies and two were employees of federal land management agencies.

The number of firefighters who died while operating on the fire ground represented 49 percent of the on-duty deaths.

The decline in firefighter deaths occurred in the following areas:

*Lowest number of sudden cardiac deaths

*Lowest number of road vehicle crashes

*No aircraft or watercraft crashes

*The number of deaths while involved in training activities is the lowest since 1999

*Lowest number of volunteer firefighter deaths ever

*Lowest number of career firefighter deaths (tied with 1993)

*Lowest number of deaths while responding to or returning from alarms

The NFPA considers on-duty fatalities to include those resulting from injuries, illnesses and fatal mishaps involving nonemergency occupational hazards.

The organization's criteria differs from that of the U.S. Fire Administration, as it does not include fallen firefighters included under the Hometown Heroes Act.

The Hometown Heroes Survivors Benefit Act -- passed in 2003 -- presumes that a heart attack or stroke is in the line of duty if the firefighter was engaged in stressful or strenuous physical activity while on-duty and the firefighter became ill while on-duty or within 24 hours.

In 2011, the USFA counted 81 firefighters as having died while on duty, 19 of which were classified as Hometown Heroes.